Running 575v 3-phase from 240v 1-phase?

[kikivara]

Hi everyone, I've recently acquired a Maxport Vertical Milling Machine with a 3 HP, 3-phase, Tung Hsing Induction Motor that runs on 575v. However, my power source is only 240v, 1-phase. I know this topic has been discussed many times, but I'm still struggling to figure out the best solution for my situation, and I would appreciate any advice or guidance on how to properly run this machine from my current power source. I have attached pictures and the motor specs below for reference. Thank you in advance for your help!

 

[johansen]

Pull the motor apart and see if you can find the hidden star point. Then wire it as delta.

Run the now 346 volt motor from a cheap 3hp 240 volt vfd..

But program the vfd for 350 volts 60hz. (Or 240v 42hz)

If 2hp at 40hz isnt enough for you, cross that bridge later

 

[BT Fabrication]

you need to buy a phase converter, then a transformer to step up the voltage to the proper 575V. So this will cost you about $1500 for a transformer and probably the same for a phase converter then a few hundred in wire.

 

[Overland]

Probably simplest to replace the motor.
Looks like a generic Taiwan Bridgeport clone.
The absolute best way to do this, done it myself, is to replace motor with a good quality 3 phase 240 volt motor. Remove all the variable pulley system, and put a 1,750 rpm motor with a 1:2 single belt pulley arrangement (3" pulley on motor, 6" on machine shaft). This will give you about about 850 rpm at 60 Hz.
Use a good quality VFD, like this Fuji below, $284. This will give you 3 phase.
Get an inverter ready 3 phase motor that will allow to run up to twice normal 60 Hz speed.
Use the VFD to control spindle speed.
I can drill 3/4" holes in steel plate at about 20 Hz (280 rpm) on my machine in high gear.
You will be very pleased with results.
Bob,
PS, where are you ? put it on your profile.

VFD, 5hp, 19.1A, 230VAC, 3 Phase Input, Compact Mi

VFD, 5hp, 19.1 Amp (19.1A), 230VAC, 3 Phase Input, Compact Micro Drive, Easy To Use, IP20 UL Open Type, 7.09 x 5.51 x 5.47" (HWD), Optional NEMA/UL 1 Kit: NEMA1-C2-301 and Optional DIN Rail Mounting Adapter: RMA-C1-3.7 Available to Order Separately, Constant Torque (CT) Rated, FRENIC-Mini Series

www.wolfautomation.com

 

[Hopefuldave]

I got around a 415-only motor on 240 by putting a step-up before the RPC - the transformer is an old oil-cooled welder with the low voltage winding stripped off and a new secondary wound on a 3D-printed spool to fit the laminations - fairly easy to work out the turns ratio,wind 10 turns of insullated wire around the laminations where the low-voltage winding was, power to the primary and measure the RMS voltage on the test winding, divide the wanted voltage by that and that's how many tens of turns you need - add a few extra windings in case you need to boost or buck the voltage, THEN you can start to work out how to build the RPC, what idler it needs...

Or, quicker, easier, as suggested, buy a replacement 220v motor and a suitable VFD, you're pretty much done!

Dave H. (the other one)

 

[johansen]

I got around a 415-only motor on 240 by putting a step-up before the RPC - the transformer is an old oil-cooled welder with the low voltage winding stripped off and a new secondary wound on a 3D-printed spool to fit the laminations - fairly easy to work out the turns ratio,wind 10 turns of insullated wire around the laminations where the low-voltage winding was, power to the primary and measure the RMS voltage on the test winding, divide the wanted voltage by that and that's how many tens of turns you need - add a few extra windings in case you need to boost or buck the voltage, THEN you can start to work out how to build the RPC, what idler it needs...

Or, quicker, easier, as suggested, buy a replacement 220v motor and a suitable VFD, you're pretty much done!

Dave H. (the other one)

And i thought my suggestion was the hard way.

Op can get 2hp at 40hz from a 240v vfd by reconnecting thr motor for delta.. which is likely less work than replacing the motor

 

[Hopefuldave]

And i thought my suggestion was the hard way.

Op can get 2hp at 40hz from a 240v vfd by reconnecting thr motor for delta.. which is likely less work than replacing the motor

Probably is, but my Holbrook has a 415-only 3-speed motor (although it's now run from a hacked-at-home VFD that makes 415 from 240 between 10 and 85 Hz, to give lower and higher spindle speeds), and the standard in Europe (and most of the world) is 3-phase 50 Hz around 400v (Europe, e.g., was mostly 380v with "local variations", now thanks to "harmonisation" it's standardised at 400 +/- 5% - so includes 380 - 420) - having 415 on tap means I can plug anything into the Big Red Sockets straight from the factory/auction without having to rewire / dig out star points it even runs my 415v 3-phase inverter TIG happily (as long as I don't turn the current up to the full 350A).
Making the transformer up was pretty easy - 3D printed bobbin for the new winding, rotary table driven by a pistol drill, 3mm enamelled wire zigzagged through some bearings to straighten and tension, then bagged and vacuum impregnated with epoxy and laminations threaded back through. Design/build of the rotary converter took much longer!

Dave H. (the other one)

 

[DDoug]

Probably is, but my Holbrook has a 415-only 3-speed motor (although it's now run from a hacked-at-home VFD that makes 415 from 240 between 10 and 85 Hz, to give lower and higher spindle speeds), and the standard in Europe (and most of the world) is 3-phase 50 Hz around 400v (Europe, e.g., was mostly 380v with "local variations", now thanks to "harmonisation" it's standardised at 400 +/- 5% - so includes 380 - 420) - having 415 on tap means I can plug anything into the Big Red Sockets straight from the factory/auction without having to rewire / dig out star points it even runs my 415v 3-phase inverter TIG happily (as long as I don't turn the current up to the full 350A).
Making the transformer up was pretty easy - 3D printed bobbin for the new winding, rotary table driven by a pistol drill, 3mm enamelled wire zigzagged through some bearings to straighten and tension, then bagged and vacuum impregnated with epoxy and laminations threaded back through. Design/build of the rotary converter took much longer!

Dave H. (the other one)

OP did not indicate that they were retired or working a government job where they could potter around for months on end.
I make 600 vac 3 phase, 240 vac RPC into a xformer.
All with purchased parts, nothing homebrewed to negate any/all fire insurance.

 

[Hopefuldave]

OP did not indicate that they were retired or working a government job where they could potter around for months on end.
I make 600 vac 3 phase, 240 vac RPC into a xformer.
All with purchased parts, nothing homebrewed to negate any/all fire insurance.

True, but makes one wonder why there's so much info' on homebrewing RPCs if everyone just goes out and buys them - this sub-forum has more than a handful of posts on that subject?
Fine if you can justify the cost of a COTS solution, but a significant fraction of the subforum is precisely about homebrewing and doing it safely and economically. My "pottering around for months on end" took a few spare evenings, any delays were waiting for deliveries (most of them overnight) as e.g. I didn't have enough 3mm ECW on hand. And waiting overnight for the 3D printer to finish the bobbin, time well-spent drinking single malt and sleeping

Dave H. (the other one)

 

[rons]

Get a 240 vac motor and recycle what you have. Eventually the recycled bits will make it back to where they came from.

 

[DDoug]

True, but makes one wonder why there's so much info' on homebrewing RPCs if everyone just goes out and buys them - this sub-forum has more than a handful of posts on that subject?
Fine if you can justify the cost of a COTS solution, but a significant fraction of the subforum is precisely about homebrewing and doing it safely and economically. My "pottering around for months on end" took a few spare evenings, any delays were waiting for deliveries (most of them overnight) as e.g. I didn't have enough 3mm ECW on hand. And waiting overnight for the 3D printer to finish the bobbin, time well-spent drinking single malt and sleeping

Dave H. (the other one)

Do you excell in xformer design sir ?
Has your new bobbin been safety tested ?
Try the Harry Homeshop forum please.

 

[JST]

Do you excell in xformer design sir ?
Has your new bobbin been safety tested ?
Try the Harry Homeshop forum please.

When transformers are made with wrapped wire and paper on a cardboard form, varnished, the question seems a little extreme.

But to be fair here, printed plastic parts are quite porous, which is not good for electrical uses. And I do not know if any of the filaments are UL94V0, which bobbins should be, nor what the melting points are. You do not want the bobbin to melt at operating temp........

Bobbins with spaced apart sections are the norm. Eh, I'd pass, but it's likely not a serious issue if the spacing is kept to 4mm or so and the material is suitable.

 

[Hopefuldave]

When transformers are made with wrapped wire and paper on a cardboard form, varnished, the question seems a little extreme.

But to be fair here, printed plastic parts are quite porous, which is not good for electrical uses. And I do not know if any of the filaments are UL94V0, which bobbins should be, nor what the melting points are. You do not want the bobbin to melt at operating temp........

Bobbins with spaced apart sections are the norm. Eh, I'd pass, but it's likely not a serious issue if the spacing is kept to 4mm or so and the material is suitable.

Helps it they're submerged in transformer dielectric oil, too, and exceed UL and CE creepage distances, were Hi-Pot tested beyond EU approvals spec voltage (2kv) - and yes, well enough versed in transformer construction from 50Hz up to a couple of hundred MHz, a kilowatt or more, thanks. Afraid I don't have a high horse to get on, can I borrow yours, DDoug?

Dave H. (the other one)